1. Field of the Invention
The present invention relates to facsimile machines, and more particularly to facsimile transmission from a personal computer through a secure modem.
2. Discussion of the Background
Commercially available digital interfaces provide an interface between a facsimile machine and a modem. The digital interface consists of an RS232 port mounted on a facsimile machine to communicate to external modems aboard secure telephone units (STUs). Normally, these interfaces use standard proprietary protocols for communication. For example, facsimile machines model number SFX80M and model 3500M manufactured by Ricoh are equipped with these interfaces. FIG. 1 is a block diagram illustrating a conventional facsimile communication link using such interfaces. A communication link 100 is coupled to first and second secure telephone units 102 and 104, respectively, each including a modem. First and second facsimile machines 106 and 108, respectively, are coupled to respective secure telephone units 102 and 104.
There are also interfaces in the market that interface personal computers to facsimile machines. These units enable personal computers to use the facsimile machine's external modems to transmit and receive data from telephone lines. FIG. 2 is a block diagram of a conventional system using such interfaces. A communication link 202 is coupled to first and second facsimile machines 204 and 206, respectively. A computer 208 is coupled to the first facsimile machine 204.
However, at the present time, there are no systems for sending a facsimile from a personal computer over a secure modem without purchasing special hardware for the personal computer.